https://developer.oculus.com/documentation/unity/latest/concepts/unity-req/

Compatibility and Version Requirements

Recommended Unity Versions

We recommend using one of the following Unity versions for all Oculus development.

• 2017.4 LTS
• 2018.4 LTS
• 2019.1.2f1

Our Troubleshooting and Known Issues page describes known issues with specific versions on Unity.

The minimum supported version for Oculus development is Unity Editor version 2017.4.11f1.

The optional Oculus Utilities for Unity package offers additional developer resources, and includes the latest version of OVRPlugin. When you import Utilities for Unity into a project, if the OVRPlugin version included with the Utilities is later than the version built into your editor, a pop-up dialog will give you the option to update it in your project. We always recommend using the latest available OVRPlugin version. For more information, see OVRPlugin